Cord-blood tyrosine levels in the full-term phenylketonuric fetus and the "justification hypothesis".

The "justification hypothesis" attributes mental retardation in phenylketonuria (PKU) to an inability of the heterozygous mother to deliver an appropriate amount of tyrosine to the PKU fetus who, in turn, is unable to correct for this deficiency because of its genetic constitution. We tested this hypothesis by measuring concentrations of tyrosine and phenylalanine in cord blood obtained at delivery from nine infants with PKU and five infants with persistent (non-PKU) hyperphenylalaninemia (PHP). For each of these specimens there were four control cord-blood specimens from infants born on the same day and, generally, in the same hospital.

Ecology of Streptococcus faecium bacteriophage in chicken gut.

The interaction in the chick gut between Streptococcus faecium and its phage was examined. In conventional chicks, large numbers of S. faecium and phage were found in the cecum and smaller numbers were found in the anterior gut.

Galactose-1-phosphate uridyl transferase deficiency due to Duarte/galactosemia combined variation: clinical and biochemical studies.

The most common abnormality detected by the screening of newborn infants for galactosemia is a deficiency of galactose-1-phosphate uridyl transferase due to the presence in one individual of allelic genes for the Duarte variant and for galactosemia. Clinical studies of ten untreated individuals with this genetic compound, including three adults, failed to reveal evidence of cataracts, liver disease, or mental subnormality, the major clinical complications associated with galactosemia. Galactose-1-phosphate was not detectable in umbilical cord blood from one infant.

Rennes-like variant of galactosemia: clinical and biochemical studies.

The first recognized case of a Rennes-like variant form of galactosemia in a Caucasian individual is described. Galactose-1-phosphate uridyl transferase activity was approximately 10% of the normal in both erythrocytes and cultured skin fibroblasts. Electrophoretic mobility of the variant enzyme in erythrocytes was slower than that of normal individuals and identical to that of the two cases originally reported from Rennes, France.

The isolation, partial characterization, and subfractionation of human intestinal brush borders.

Brush borders were prepared from small intestinal specimens obtained from 20 patients who underwent abdominal surgery. Some enzyme constituents of the brush borders and fractions obtained from them by papain digestion are described.